Heckler stem lenght for light FR

I currently have a 100mm stem on my large Heckler for trail riding. At 6' tall it's a nice for trail riding. It's already what I feel is a nice compact cockpit and don't want to go to small.

I went to a local ski area to ride and feel the need for a shorter stem. What length should I be looking for to be able to DH and lift the front easier without making the cockpit too small to ride. Any thoughts or suggestions are welcome. Thanks